1. Field of the Invention
The present invention generally relates to a circuit breaker with a switch latch moveable by means of a manual operating handle for the purpose of switching the breaker on and off, and a supporting lever which is moved along therewith. One end of the lever is pivotable about a fixed axle, and the other end of the lever co-operates with a latch. The circuit breaker also includes a toggle system with an upper and a lower toggle connected together in an articulated manner by means of a toggle axle. The upper toggle can be coupled to the supporting lever, and the lower toggle can be coupled to a contact carrier. The contact carrier can be provided with moveable contact members and can be connected to a selector shaft. An actuating spring can be arranged between the switch latch and toggle axle and can act upon the toggle system, and a reversing lever prevents the transfer of the manual operating handle into the switched "off" position when the moveable contact members are blocked in the "on" position due to welding.
2. Background Information
Circuit breakers with a blocking lever countering the transfer of the manual operating handle into the switched "off" position when the moveable switch mechanism is blocked in the "on" position are disclosed, for example, in German Utility Model No. 80 23 509, German Patent No. 30 33 213, and U.S. Pat. No. 4,165,453.
In accordance with safety requirements, when contacts are welded, the operating handle of a switch or circuit breaker essentially must not be able to be put into the "off" position in order to avoid locking of the switch with welded contacts.